Kitchen Hood Size vs Range Size: How to Match Hood Width to Cooktop Width

Start with the Cooktop: Why Width Sets the Baseline

The range or cooktop width is the fixed number you build around. Most residential ranges are 30 inches wide, with 36-inch models common in larger kitchens and 24-inch units in compact layouts. The hood you choose must cover the cooking surface's full width, because the ventilation system only captures what passes directly beneath it. If the hood is narrower than the cooktop, the outer burners release steam, smoke, and grease that drift past the fan and settle on cabinets and ceilings.

The general rule is that a hood should be at least as wide as the cooktop, and ideally wider. A 30-inch range pairs well with a 30-inch hood for a flush look, but a 36-inch hood over a 30-inch range gives a margin that captures more rising air. The extra width matters most when you use the front burners, which sit closer to the edge of the hood's capture zone.

Measure the cooktop from outer edge to outer edge, not just the burner layout. A range with a griddle or a built-in downdraft may have a wider overall footprint than the burners suggest, and the hood must cover that full surface. Write this measurement down before you look at any hood specs.

• Measure the full cooktop width, edge to edge.
• Note the burner layout and whether front burners are the ones you use most.
• Decide whether you want a flush match or an overhang for better capture.

Stage 1: Choose a Hood Width Equal to or Wider Than the Range

For a 30-inch range, the minimum hood width is 30 inches. A 36-inch hood is the most common upgrade because it adds 3 inches of capture on each side without looking oversized in most kitchens. For a 36-inch range, the minimum is 36 inches, and a 42-inch hood gives that same protective overhang. Going wider than 42 inches over a 36-inch range starts to look disproportionate unless the hood is a deliberate design feature.

The exception is a cooktop placed against a wall with no side clearance. In that setup, a hood exactly matching the cooktop width works fine because the wall contains the sideways drift of smoke and steam. On an island or a peninsula, where air can escape on all sides, the wider hood matters more. Island installations also need a taller capture area because there is no back wall to help funnel the airflow.

A hood that is wider than the range does not reduce its efficiency; it improves it. The fan moves the same volume of air, but the larger canopy catches more of the plume before it spreads. The trade-off is visual: a hood much wider than the range can make the cooktop look small and can interfere with upper cabinets if you are installing under a cabinet rather than a wall-mounted or island hood.

Stage 2: Account for CFM Before You Settle on Size

Width alone does not determine whether a hood clears the air; airflow rating, measured in cubic feet per minute (CFM), does the actual work. A 36-inch hood with 400 CFM will underperform a 30-inch hood with 600 CFM when you are searing or frying. The sizing rule many installers use is 100 CFM per 10,000 BTUs of gas burner output, or 100 CFM per linear foot of electric cooktop width for electric models.

For a typical 30-inch gas range with 40,000 total BTUs, that rule suggests 400 CFM. But if you cook with high heat often, or if the kitchen is open to other rooms, going up to 600 CFM gives a comfortable margin. The hood width still matters because even a high-CFM fan cannot capture air that rises outside its canopy. Size and airflow work together: the width defines the capture zone, and the CFM defines how fast air leaves the kitchen.

Makeup air becomes a consideration above roughly 400 CFM in tightly sealed homes. A powerful fan can depressurize the house, pulling exhaust fumes back down the flue of a gas water heater or furnace. Local building codes in many areas require a makeup air system for hoods rated above 400 CFM, so check with your installer or building department before buying a high-output model.

Stage 3: Set the Mounting Height for the Hood You Choose

The distance between the cooktop and the bottom of the hood affects how well the width works. For gas ranges, the standard clearance is 24 to 30 inches from the cooking surface to the hood's underside. For electric cooktops, the range is 18 to 24 inches because there is no open flame to worry about. These numbers come from manufacturer instructions and local codes; the hood's manual may specify a tighter range, and you should follow it.

A hood mounted too high loses capture efficiency because smoke and steam spread out before reaching the fan. A hood mounted too low can be a hazard with gas flames and can block your view of the back burners. Within the allowed range, you can tune the height to your own height: taller cooks can mount the hood a little higher and still reach the controls, while shorter cooks may prefer a lower mount.

The capture width effectively shrinks as the hood gets higher. At the minimum clearance, the canopy catches a fairly tight plume. At the maximum, the same canopy must catch a wider, cooler plume that has had more room to spread. If you must mount high, choose the wider hood option to compensate.

Stage 4: Match the Hood Style to the Space, Not Just the Numbers

The width rule applies differently across hood types. Under-cabinet hoods are limited by the cabinet width above them, so a 30-inch cabinet usually means a 30-inch hood even if a 36-inch would capture better. Wall-mounted chimney hoods give you more freedom because they attach to the wall and vent through the ceiling or wall. Island hoods hang from the ceiling and can be any width, but a very wide island hood needs a matching duct and a fan strong enough to move air across that larger opening.

Ducted hoods move air outside and are the most effective; ductless (recirculating) hoods pass air through a charcoal filter and return it to the kitchen. A ductless hood needs a higher CFM rating to achieve the same perceived performance because the filter adds resistance. If you are limited to ductless, matching or slightly exceeding the range width becomes more important, since the weaker airflow relies more on the canopy shape to catch the plume.

The hood's depth also matters, though it is less discussed than width. Standard hoods are about 18 to 20 inches deep, which covers the burners on a typical 25- to 26-inch-deep range. Some island hoods are shallower for looks; if the hood is noticeably shallower than the cooktop, the front burners sit outside the capture zone even if the widths match. Check the depth spec before you buy.

Stage 5: Verify Fit with a Template Before Cutting Anything

Once you have chosen a hood width, test the fit before you cut ductwork or cabinets. Most hood manufacturers provide a paper template showing the exact footprint, mounting bracket locations, and duct position. Tape the template to the wall or ceiling above the range and confirm it clears upper cabinets, windows, and trim. Check that the duct path from the hood to the outside is straight and short; every bend reduces airflow and may require a larger fan.

If you are replacing an existing hood, measure the old unit's mounting holes and duct size before ordering. A new hood may have a different duct diameter, commonly 6 or 8 inches, and you may need a transition piece. The width of the new hood should match or exceed the range, but it does not have to match the old hood's width; the mounting holes can be patched and repainted if the new unit is wider.

Finally, compare the hood's listed width to its actual installed width. Some hoods have a decorative outer shroud that is wider than the functional canopy, and some under-cabinet hoods have a narrower capture area than the overall body. The number that matters is the canopy's inner opening, not the outer trim. If the specs only list overall width, ask the manufacturer or look for the capture area measurement in the installation manual.

Common Sizing Mistakes and How to Avoid Them

The most frequent mistake is choosing a hood narrower than the range to save money or fit a tight cabinet. This guarantees that steam from the outer burners escapes, and it is hard to fix later without replacing the hood. A second common error is buying a very wide hood with a weak fan; the large canopy looks impressive but does not clear the air if the CFM is too low for the cooktop's output.

Another mistake is ignoring the hood's depth when comparing widths. A 36-inch-wide hood that is only 16 inches deep may not cover a 30-inch range's front burners, especially if the range is deeper than standard. Measure the range depth as well, and look for a hood with a depth of at least 18 inches unless the design intentionally uses a smaller capture area.

Finally, do not assume that a bigger hood always means better ventilation. An oversized hood over a small range can create drafts that blow the cooking plume away from the capture zone, and it can look out of place in a small kitchen. The goal is a hood that covers the cooktop fully, has enough CFM for your cooking style, and fits the room's proportions.

Final Check: What to Confirm Before You Order

Before you place the order, write down three numbers: the cooktop width, the hood width, and the hood's capture area width. Confirm that the hood width is at least equal to the cooktop width, and ideally 3 to 6 inches wider. Confirm the capture area, not just the outer trim, covers the full cooking surface. Then confirm the CFM matches your burner output or electric cooktop size, and that the duct size and mounting height match your kitchen's constraints.

If you are working with a contractor, share these numbers before they rough in the ductwork. It is much easier to change a hood model before the duct is installed than after. If you are installing yourself, read the hood's installation manual fully before cutting; most returns are the result of an unopened manual.

When the numbers line up, the hood will do its job quietly: no lingering smoke, no greasy cabinets, and no heat shimmer above the front burners. The width rule is simple, but it only works when you apply it alongside depth, CFM, and height.